Anti-lowering device for a loader boom

ABSTRACT

A pair of locking pins each disposed at a predetermined height adjacent a respective side wall of a loader and operative to be selectively moved outwardly therefrom such that the outer portions thereof project through the vertical planes of a pair of boom arms, thereby prohibiting the boom arms from lowering beyond the predetermined height.

o Waited States Patent 1 1 [111 3,7%,362 Hurlburt et al. May 1, 1973 ANTH-LOWERING DEVICE FOR A 3,094,231 6/1963 Dempster ..214/302 LOADER BOOM 1,445,571 2/ i923 [75] Inventors: Joseph C. l-lurlburt, Leola; John L. Smhle" Ephrata 1,773,163 8/1930 Becker ..I87/75 [73] Assignee: Sperry Rand Corporation, New Holland, Pa. Primary Examiner-Gerald M. Forlenza Assislanl Examiner-John Mannix [22] Flled' Sept 1971 Attorney-John C. Thompson, Joseph A. Brown and [2]] Appl. No.: 178,972 James J. Kennedy 52 U.S. c1 ..214/140, 214/142 [57] ABSTRACT CL I. -;.E02f A pair of locking pins each disposed at a predeter [58] Fleld of Search ..2l4/142, 770, 302, mined height adjacent a respective side n of a 214/308 673; 187/75; loader and operative to be selectively moved out- 296/56 35 A wardly therefrom such that the outer portions thereof project through the vertical planes of a pair of boom [56] References Clted arms, thereby prohibiting the boom arms from lower- UNITED STATES PATENTS ing beyond the predetermined height.

3,215,292 11/1965 Halls ..2l4/770 1 Claim, 4 Drawing Figures PATEN-TEDB'AYI 'ms FIG?) INVENTOR JOSEPH c. HURLBURT BY J. LESTER STOHLER ATTORN EY ANTI-LOWERING DEVICE FOR A LOADER BOOM BACKGROUND OF THE INVENTION The present invention relates to loaders and the like and more particular to a locking mechanism for employment therein to selectively prohibit a boom structure from lowering beyond a given height.

Conventional loaders are normally provided with a bucket carrying boom structure that moves up and down adjacent the outer sides of the loaders body. For various convenience reasons such as inspection or repair, the operator sometimes desires to maintain the bucket and boom structure in an elevated position for more than a momentary period of time. Since many of the conventional loaders today employ hydraulics for powering the loader boom, it is desirable to provide a secondary locaking mechanism to prevent the' boom structure from suddenly lowering due to a failure in the hydraulic system. Moreover, in a raised stationary position, for long time periods, substantial stress is encountered by the various structural links of the boom structure. Also as a practical matter, there is often some internal leakage with the boom s hydraulic system which, of present, gives rise to a gradual downward drift when the boom is left in an elevated position. Thus, it is desirable to provide a locking or anti-lowering device that would support the boom structure during these extended periods of elevation, thereby relieving at least some of the stress being endured by the boom structure.

SUMMARY OF THE INVENTION In view of the foregoing remarks, applicants have provided a loader with an anti-lowering device that is adapted to prevent the loaders boom structure from lowering below a predetermined height when actuated. In particular, applicants anti-lowering device basically comprises a pair of locking pins movably mounted adjacent respective sides of the loaders main frame and movable outwardly therefrom so as to project through the vertical planes of the loaders boom structure. The locking pins are further provided with a linkage arrangement that when actuated moves both of the It is therefore the principal object of the present invention to provide an anti-lowering device for employment within a loader having a boom structure that is adapted to move up and down along the outside portions of the loaders main body frame.

Another object of the present invention resides in the provision of a pair of locking pins normally disposed adjacent respective sides of a loader and movable therefrom to an outer position that projects through the vertical planes of the loaders boom structure, the loaders boom structure being comprised of corresponding laterally spaced boom arms disposed on each side of the loaders main body and operative to move up and down therealong'for supporting and carrying a material handling implement such as a bucket.

A more particular object of the present invention is to provide the pair of locking pins with an interconnecting linkage structure that is adapted to actuate the two locking pins simultaneously between the nonlocked and locked positions.

A further object of the present invention is to provide a pair of locking pins of a generally cylindrical shape at a predetermined height within the loader and to dispose said cylindrical locking pins such that their elongated axis extends transversely of the loader such that when actuated to the locked positions the outer ends of the cylindrical shape locking pins project through the vertical planes of the loaders boom structure, thereby prohibiting the boom structure, if elevated, from lowering beyond the position of the cylindrical locking pins.

Other objects and advantages of the present invention will become apparent and obvious from a study of the following description and the accompanying drawings which are merely illustrative of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a loader having a boom structure in a raised position and with the antilowering device of the present invention engaged with the boom structure for prohibiting the boom structure from lowering beyond a predetermined height.

FIG. 2 is a view taken along the line 2-2 of FIG. 1 showing a front elevational view of the anti-lowering device in its normal non-locked position.

FIG. 3 is a view similar to FIG. 2 except that the antilowering device is in the locked position.

FIG. 4 is a view taken along the line 4-4 of FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT With reference to the drawings, particularly FIG. I, a front end loader is indicated generally by the number 10. The loader 10 is provided with a chassis structure comprised of a pair of laterally spaced elongated drive housings 16, the drive housings being of a generally enclosed structure for containing a chain drive, not shown, in a lubricant solution for driving a pair of front rotatively mounted wheels 12 and a pair of rear rotatively mounted wheels 14 (only one of which is shown). Carried by the drive housings 16 is a main frame 18 which includes a pair of laterally spaced side walls 20 and a rear engine compartment 22, the rear engine and related drive components not being shown in this particular case because such is immaterial to the present invention.

A cab extends over a central portion of the main body frame 18 and generally defines an operators station therebeneath. The cab is made up of a pair of laterally spaced vertically upstanding front support posts 26 which extend from the main body frame 18. Spaced rearwardly of the front support post 26 are a corresponding pair of rear support posts 28. Mounted across the top of the front and rear posts 26 and 28 is a roof structure 30. Disposed forwardly of the cab structure and adjacent the front support post 26 are a pair of partially open A-frame panels 32.

The present loader further includes a boom structure indicated generally by numeral 34 in FIG. 1. The boom structure 34 is basically comprised ,of a pair of corresponding upper boom arms 36 and a pairof corresponding lower boom arms 38. The lower boom arm 38 is pivotally secured to a respective side of the loader l0 and extends generally rearwardly therefrom. Each upper boom arm 36 has one end extremity pivotally connected to the rearmost extremity of a lower boom arm 38 and extends generally upwardly therefrom for a short distance and then bends generally forward and projects therefrom past the forwardmost portion of the loader 10. The front portion of the upper boom arms 36 is adapted to receive a material handling implement, which in the embodiment shown in the present application is a bucket 44.

To support the boom structure 34 and to provide additional guidance therefore, a pair of support links 40 are pivotally interconnected between a forward portion of the cab and a rear portion of the upper boom arms 36. As in most commercial heavy duty loaders, the boom structure is powered by hydraulics and in the present case two hydraulic cylinders 42 are pivotally connected at the cylinder to a side portion of the loader just above the pivotal connection of the lower boom arm 38 with the loader. The rod portion of the cylinders 42 are pivotally connected to a rear intermediate point on the upper boom arms 36. Although the boom structure has been described briefly, a more detailed appreciation and unified understanding of the boom structure can be gained from a study of US. Pat. No. 3,215,292 granted to L. M. Halls on Nov. 2, I965.

The anti-lowering device for the loaders boom structure is indicated generally by numeral 45 and is shown particularly in FIGS. 24. Viewing the anti-lowering device in detail, it is seen that the device is disposed along a transverse mounting panel 46 that is situated behind the operators station. It is noted that the transverse mounting panel extends between the laterally spaced side walls 20 of the loader. With particular reference to FIGS. 2 and 3, it is seen that a pair of sleeves, each indicated by the numeral 48, and disposed along the transverse mounting panel 46 and extends laterally thereacross with the outer portions thereof extending slightly through the side walls 20. Slideably contained within each of the sleeves 48 is a generally cylindrical shaped locking pin 50, the two pins being linked together by a pair of connecting links 52,54 and a pivot bar or plate 56 that is rotatively mounted about a longitudinal axis 57. It is noted that the outermost ends of links 52 and 54 are connected to the innermost ends of the locking pins 50 while the innermost ends of the same connecting links 52 and 54 are pivotally connected to the pivot plate 56. Therefore, the clockwise rotation of the pivot plate, as viewed in FIGS. 2 and 3, results in the outward movement of the locking pins 50 through their respective sleeves such that the outer portions of the pins extend from the outer portions of the sleeves 48 through the vertical plane of the lower boom arms 38. (FIG. 3) And likewise, the counterclockwise movement of the pivot plate 56, as viewed in FIGS. 2 and 3, results in the retraction of the pins 50 from the outward position to the inward position as shown in FIG. 2.

To provide for quick and convenient actuation of the pins 50, a side linkage is provided that is particularly disposed adjacent the operator's station. This linkage arrangement is shown in FIGS. 2-4 and is basically comprised of a handle 58 that is inter-connected to a bell crank 60 by two successive interconnecting links 62,64. The bell crank 60 is pivotally mounted about axis 61 and is connected to pivot plate 56 by an actuating link 66. Thus, the forward movement of the handle 58, as seen in FIG. 4, causes the two interconnecting links 62,64 to drive the bell crank upwardly, causing it to rotate about its axis 61 in a counterclockwise direction (as viewed in FIGS. 2 and 3) which results in the lateral movement of the actuating link 66. The lateral movement of the actuating link 66 caused by the counterclockwise rotation of the bell crank results in the clockwise rotation of pivot plate 56, thereby causing the locking pins 50 to project through the vertical plane of the lower boom arms 38. To retract the pivot pins 50 from the outward position, as shown in FIG. 3, the handle 58 is shifted rearwardly, as shown in FIG. 4, causing the two interconnecting links 62 and 64 to rotate the bell crank 60 clockwise. The clockwise movement of the bell crank 60 results in counterclockwise movement of pivot plate 56. The counterclockwise movement of pivot plate 56 causes the pair of cylindrical locking pins 50 to be retracted to the inward position (FIG. 2).

Thus, when the boom structure 34 is raised to an elevated position and the operator desires to maintain the boom structure in that position for a period of time, he will actuate the anti-lowering device 45 in a manner just described. When the anti-lowering device is actuated the pins 50 will extend outwardly from the sides 20 of the main frame 18 so as to protrude through the vertical plane of the lower boom arms 38. Should a failure occur in the hydraulic system or for any other reason the boom structure should begin to fall, the presence of the locking pins 50 in the extended position, as shown in FIG. 3, will prevent the boom structure from lowering beyond a predetermined height.

It is obvious from the foregoing discussion that the present invention has the advantage of being simple and easy to construct while performing a useful and worthwhile function in the loader. Moreover, the present anti-lowering device is disposed in a location which lends convenience to the operator in actuating the locking pins laterally back and forth between the retracted and extended positions.

The terms, upper, forward, rearward etc. have been used herein merely for the convenience of the foregoing specification and in the appended claims to describe the anti-lowering device and its parts as oriented in the drawings. It is to be understood, however, that these terms are in no way limiting to the invention since the anti-lowering device may obviously be disposed in many different positions when in actual use.

The present invention, of course, may be carried out in other specific ways than those herein set forth without departing from the spirit and essential characteristics of the invention. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, and all changes coming within the meaning and equivalency range are intended to be embraced herein.

Having thus described our invention, what we claim is:

1. An anti-lowering device for a loader boom comprising, in combination, a wheel supported chassis; a main body frame carried by said chassis including a pair of generally vertically extending laterally spaced apart side walls; a boom structure pivotally secured to said main body frame, said boom structure including a pair of laterally spaced apart corresponding boom arms adapted to be movable in a substantially vertical path position to an outward extended position where the outer portions of said pins project outwardly into the path of travel of said boom structure whereby said boom structure may be lowered into engagement with said locking pins, said pins supporting said boom structure and prohibiting further downward movement of said boom structure below the predetermined height. 

1. An anti-lowering device for a loader boom comprising, in combination, a wheel supported chassis; a main body frame carried by said chassis including a pair of generally vertically extending laterally spaced apart side walls; a boom structure pivotally secured to said main body frame, said boom structure including a pair of laterally spaced apart corresponding boom arms adapted to be movable in a substantially vertical path outwardly of said side walls; a pair of locking pins each mounted at a predetermined height on said side walls for slidable longitudinal movement relative to said main body frame and to said boom structure inwardly of said boom structure, said pair of locking pins being disposed one on each side of said main body frame, and means interconnecting said locking pins for simultaneously actuating said pins between an inward retracted position to an outward extended position where the outer portions of said pins project outwardly into the path of travel of said boom structure whereby said boom structure may be lowered into engagement with said locking pins, said pins supporting said boom structure and prohibiting further downward movement of said boom structure below the predetermined height. 